1. Field of the Invetion
The present invention relates to a connecting structure for a power cord having a circuit board arranged inside a case body, the power cord being adapted to be connected to this circuit board.
2. Description of the Related Art
In a conventional connecting structure for an AC cord of this type, a bundle of copper wires at a distal end of the AC cord is stripped in some areas of a soldered part between the AC cord and the circuit board, at a primary side of an electric power block of the circuit board. It has been a problem that while physical loads are applied to these stripped areas, the bundle of the copper wires starts to be broken, and the AC cord makes a short circuit between the two poles, which may be a cause for fire.
A first example of the connecting structure in the related art is shown in FIGS. 7A and 7B. In this structure, as shown in FIGS. 7A, 7B, a bushing 101 has a lower face formed of plastic to be in contact with a circuit board 102, and is provided with insertion holes 104 for inserting lead wires 103 in such a manner that the insertion holes gradually come close to a plane of the circuit board 102, in a direction from the back side of the bushing from which the lead wires 103 are drawn out toward the front side where the lead wires 103 are connected to the circuit board 102. Moreover, locking hooks 108 are projected from the lower face of the bushing 101 at opposite sides thereof, and engaging holes 109 corresponding to the locking hooks 108 are formed in the circuit board 102. The lead wire 103 whose distal end has been stripped by a determined length is inserted into an open hole 105 until it comes into contact with the circuit board 102, and then, the locking hooks 108 are inserted into the engaging holes 109 in the circuit board 102. A core wire 107 is forcibly bent so as to become parallel to a wiring pattern 110 of the circuit board 102, and a distal end of the core wire 107 is brought into tight contact with the wiring pattern 110. In this state, the core wire 107 is soldered to the wiring pattern 110 (Refer to JP-A-2003-189536, for example).
However, this structure has had a problem that the soldering work has been difficult, because the lead wire 103 was unable to be soldered until it had been inserted into the insertion hole 104.
A second example of the connecting structure in the related art is shown in FIGS. 8A and 8B. This is a holding structure for a lead wire of an electric component, in which the lead wire 204 connected to the electric component to be arranged on a chassis 201 of an electric appliance by fitting a panel 206 to the chassis 201, is held inside the electric appliance, as shown in FIGS. 8A, 8B. In this structure, rod-like holding projections 207, 207 in a bifurcated shape are projected from an inner wall face 214 of the chassis 201 up to a position close to an inner wall face 261 of the panel 206, and the lead wire 204 of the electric component is inserted between these holding projections 207, 207, whereby this lead wire 204 is held so as not to be withdrawn (Refer to Japanese Utility Model Registration No. 3065115, for example).
However, in this structure, the lead wire 204 has been simply fixed, but there has been no part to be soldered.
A third example of the connecting structure in the related art is shown in FIG. 9. In this structure, as shown in FIG. 9, core wires 315 are exposed and projected from insulating layers 314 on terminal ends of shielded wires 311 which constitute a flat cable 310. Current carrying paths 326 are formed on an FPC 320 at the same pitch as the core wires 315. The FPC 320 is provided with a positioning member 330 on the front side of an area where the current carrying paths 326 are formed. The positioning member 330 has wire fitting grooves 333 which are formed at a regular pitch in a shape of comb teeth for receiving the insulating layers 314. When the insulating layers 314 of the shielded wires 311 of the flat cable 310 have been respectively aligned with and pushed into the wire fitting grooves 333 in the positioning member 330, the core wires 315 are arranged at the determined pitch and respectively positioned just over the respective current carrying paths 326. Then, the core wires 315 are pressed against and soldered to the current carrying paths 326 (Refer to JP-A-2001-60469, for example).
However, in this structure, it has been concerned that a short circuit may occur in case where some of the core wires 315 have been broken on their way.